Mercury removal from wastewater by batch foam fractionation

ABSTRACT: A single batch foam fractionation column was employed to remove mercury from contaminated water having mercury concentration at trace levels. Mercuric chloride was used as a salt of mercury to provide mercuric ions while sodium dodecyl sulfate was used as a surfactant to generate foam. The concentration of the surfactant was far below the critical micelle concentration. The effect of different parameters such as surfactant concentration (100, 150, 200, 250 and 300 ppm), initial mercury concentration (1, 10, 20, 30, 40 and 50 ppm), foaming time (5, 10, 25, 45, 70, 100 and 120 minutes) and pH of the solution (1, 2, 3, 4, and 5) on the efficiency of mercury removal were investigated. The results showed that the removal efficiency increased with pH decreased, surfactant concentration increased and initial Hg2+ concentration decreased. Time for equilibrium was observed around 100 minutes. Within the ranges of variables investigated, the optimum separation conditions were observed at pH 1, 300 ppm of surfactant concentration, 1 ppm Hg2+ initial concentration, and 90 minutes foaming time.